The Endocrine Assays Laboratory generated, titered and distributed sheep antirabbit gamma globulin sera (second antibody) to NICHD Intramural Investigators, mostly in PRB, ERRB and DEB. Rigid quality control and efficient harvesting procedures were combined to provide a high quality reagent at a fraction of the commercial cost. Specific antisera against steroid hormones were provided to investigators at the University of Maryland Medical School, Baltimore, MD and at Eastern Virginia Medical School at Norfolk, VA. Preliminary studies were initiated in collaboration with Dr. Griff Ross and Dr. Donald Mattison to investigate neonatal and fetal ovarian function in vitro using a rat model. Determination of the optimal model system with respect to age, species, culture conditions, biochemical and morphological markers is in progress.